Veterinarian Kurt de Cramer delivered what is believed to be the first ever documented case of identical twin puppies at his practice in South Africa recently. What began as a regular day on the job at Rant en Dal Animal Hospital in Mogale City, ended in history making as de Cramer shockingly discovered two healthy pups sharing one placenta, according to the BBC.
The puppies, both of which had their own umbilical cords, were born to an Irish wolfhound. De Cramer performed a caesarean section on the mother after she exhibited “distress and prolonged abdominal straining” prior to giving birth.
The veterinarian noticed what appeared to be a lump of excess fluid surrounding the fetus. But when he went to remove it, shockingly discovered two fetuses.
“When I realised that the puppies were of the same gender and that they had very similar markings, I also immediately suspected that they might be identical twins having originated from the splitting of an embryo,” said de Cramer.
Veterinarian delivers identical twin puppies
In his 26 years of practicing veterinary medicine de Cramer has never delivered two pups from the same placenta. Laboratory testing confirmed his suspicions that the puppies were in fact genetically identical, a rarity among the animal kingdom.
Other than humans and one species of armadillo, scientists say that identical twins in the animal world are very rare. This is because the placenta is typically designed to support only one baby at a time. When they do develop, they often don’t survive due to lack of nutrients and oxygen.
Two years ago, de Cramer discovered two fetuses sharing a placenta but they were already dead when he performed the c-section.
“It is even less likely for placenta-sharing puppies to survive, because of several complications relating to nutrient and oxygen supply from a single placenta having to do the job that is normally done by two placentas,” de Cramer said.
Humans and a type of armadillo are the only species known to birth identical twins
While genetically identical animal twins are rare, non-identical ones are common in species such as dogs and rabbits. Identical twin fetuses have been discovered in horses, but none have survived. This is because a horse’s placenta is too weak to transport enough oxygen for two fetuses, the BBC reports.
De Cramer’s colleagues initially had their doubts about the two pups being genetically identical, not just because the occurrence is rare, but because they had slightly different markings.
However, science tells us that while identical, individual genes often express themselves differently.
“Human identical twins also have the same genes, but because those genes are expressed differently in each person, they have different freckle and fingerprint patterns,” de Cramer explained.
“The twins looked very similar,” said Carolynne Joone of James Cook University in Townsville, Australia.
“But pups from the same litter often do, [and] there were small differences in the white markings on their paws, chests and the tips of their tails. I wasn’t sure they were monozygotic [identical] at all initially.”
‘People don’t see these things unless they know to look’
De Cramer and his colleagues took DNA samples from the pups on two different occasions; first from their blood at birth, and then from their tissue six weeks later.
They also analyzed the rest of the puppies to determine how similar they were genetically, Joone explained. The lab results showed that the two pups were in fact genetically identical. The rest of the litter had similar DNA, as is typical among litter-mates, but it wasn’t identical like that of the twins.
De Cramer says that while this case of identical puppies is the first ever to be recorded, it doesn’t necessarily mean that it’s never occurred before. Since puppies of the same litter usually look similar, the pet parent might not notice twins.
Had de Cramer not performed the C-section it’s possible the pet owner never would have noticed, he said.
“Yes, there would have been one less placenta than there were pups, but as the bitch often eats the placentas the owner probably would have simply shrugged this off.”
Today the pups are happy and healthy. They were smaller at birth, but have now grown to regular size, according to the vets.